Flexible dipper stick



J1me 1932- E. H. LICHTENBERG 1,853,632

FLEXIBLE DIPPER STICK Filed April 5, 1951 2 Sheets-Sheet 1 dbtowwa p June 21, 1932- E. H LICHTENBERG FLEXIBLE DIPPER STICK Filed April 3, 1931 2 Sheets-Sheet 2 Patented June 21, 1932 UNITED STATES PATENT? OFFICE ERICH H. LICHTENBERG, F MILWAUKEE, WISCONSIN, ASSIGNOR TO KOEHRING COMI- PANY, 0F MILWAUKEE, WISCONSIN, A CORPORATION I'LEXIBLE DIPPER STICK Application filed April 3,

It is obvious that the digging instrumentalities of excavating machines are subject to hard usage and must be constructed to withstand shocks and stresses incident to the op eration of these machines, and it is well known that there is always present a likelihood of breakage of these instrumentalities from lateral impacts against various obstructions commonly present in the proximity of the digging operations.

It is the purpose of this invention to provide a construction of digging instrumentalities for power shovels and the like in which danger of breakage from lateral impacts is much reduced. More specifically the invention deals with a new form of dipper stick which is constructed so as to flex under such lateral shocks, and thereby yield to them while possessing all the required vertical rigidity. The invention also deals with a novel manner of mounting the dipper stick which is well adapted to the new form thereof.

The invention will be understood more clearly by referring to the accompanying drawings in which Fig. 1 is a side elevation of a dipper stick constructed in accordance with this invention.

Fig. 2 is a section along the line 22 of Fig. 1, looking in the direction of the arrows, and showing the details of the mounting of the dipper stick upon its boom.

Fig. 3 is a side elevation similar to Fig. 1, but showing a somewhat modified form of construction.

Fig. 4 is a perspective view of a form of casting suitable for mounting the dipper sticks of Figs. 1 and 3.

Fig. 5 is a side elevation of a pawl and ratchet mechanism employed in the modification of Fig. 3.

Fig. 6 is a perspective view of a somewhat modified form of casting, and

Fig. 7 is a sectional view showing the ap- 19s1. Serial No. 527,543.

plication of the casting of Fig. 6 to a friction block for receiving the dipper stick.

As previously mentioned,.the present invention includes the provision of a dipper stick and mounting therefor, the dipper stick. being flexible laterally beyond the normal limits of vibration, while possessing in its vertical direction all the requirements of rigidity which must be inherent in constructions of this character. This lateral flexibility will permit the dipper stick to yield to the shocks of lateral impacts so commonly encountered during operation of this class of machines, as accidental striking of the dipper or dipperstick against adjacent obstacles such as, for example, a bank where the digging operations are in progress, or against the bodies of the trucks receiving the material discharged from the dipper, as the boom carrying the dipper is swung around into discharglng position of the dipper. The

force of such impacts is frequently suflicient to break the dipper stick, whereas if the stick were sufficiently yieldable to give sufliciently under the force of the impact, the violence.

thereof will be absorbed without harm.

It is found that a dipper stick formed by securing a pair of members 10 and 11 so that when installed one member will be above the other, and forming these members .out of I elongated unitary plateswhich are flexible laterally, this danger of fracture is much reduced through the lateral bending of these members under side impact while the resulting assembly will be absolutely rigid in the plane of the digging stroke of the machine. The members 10 and 11 are disposed in edgewise relationship and preferably in the same vertical plane, being spaced apart by the spacing bar 12 riveted to each member, the spacing bar 12 being reinforced by castings 13 and 14' placed at the respective ends of the dipper stick assembly.

The casting 14 serves as a reinforcing member for.

the dipper stick and connects the stick with the boom 15. This boom may be of any construction but as shown is formed of channel or an le members having bearings a and 152) between which the dipper stick operates and between which the casting 14 is carried. This casting 14 is formed of side plates 16 and 16a riveted, or otherwise suitably secured to the members 17 and 18, which have, respectively, the corresponding guide and retaining members 17a and 17 6, 18a and 18?), which receive the members 10 and 11 of the dipper stick, there being inserted for this purpose the duplicate preformed'units or friction blocks. 19 and 20 which are of such size and shape as :to fit into the retaining members 17 a and 17 Z) and flush with the sides thereof, as indicated in Fig. 2, the friction blocks 19 and 20 being channeled or grooved for the insertion of the dipper stick members 10 and 11, and being properly secured in position by bolts or rivets as indicatedati21. These units 19 and 20 are required since the receiving spaces at 17a and 17 b are necessarily wider than .the corresponding spaces 18a and 18b.

The member 17.is also formed with the shipper shaft bearing 22 for receiving the shipper shaft 23, each of the boom members being provided with corresponding bearings 15a and 15?) into which the shipper shaft 23 is journalled to prevent the raising and lowering of the dipper stick during digging operations. 7

It will be understood that the usual cables and pulleys are provided for the reqtiired operations of the dipper stick, these. eing illustrated, but, forming nopart of this invention, need not be described in detail.

The rear ends of the dipper stick members 10. and 11 are. secured .to a. tapering casting 25, whichrigidly reinforces the rear portion of the dip-per stick members. V Fig. 3 shows a somewhat different form of mounting of the dipper stick memberslO and 11. In this form the forward reinforcing casting 26'has operating'therein a drum 27 operating on a shaft 28 and carrying a ratchet 29 cooperating with the pawl. The purpose of this arrangement is to assure the racking cable 31 being taut at all times, the cable 31 also passing around the pulley 32 which operates between the bearing 22 and the bearing member 15a carried by the boom Y and serving as journals for the shipper shaft,

since these members are flexible laterally but 3 rigid vertically, it will be apparent that there results a dipper stick construction which will be rigid with respect to carrying the weight of the load in the dipper, while laterally yieldable under the influence of the shocks of lateral imp-acts, the lateral flexibility of the stick reducing to absolute minimum the dam er or likelihood of fracture.

I The members 19 form friction shoes in the shipper or guiding head provided by the member 17, and for facilitating the free sliding of the upper and lower parts 10 and 11 respectively of the dipper stick, in said members 19 and 20 which are counterparts, oil. grooves may be provided. These oil grooves are seen at the innermost portion of the grooves orv guiding recesses in the parts 19 and.20.

The cable means for crowding out the dipper and for racking it in'may be any conventional means or, ifdesired, shipper mechanism of the well known rack and pinion type may be employed by modification of the formofthe stick parts toprovide a crowding racln As shownin Fig. 1, the cable crowding 'means involves acable 4O deadsended on the outerend of the boom passingabout a sheave I 41 carried by. the dipper,thence over a sheave 42on the end of the boom under a sheave 43 a short distance from the end of the boom, over a crowding sheave 44 carried by the casting '25 at the upper or rear end of the stick and under a sheaves 45 also carried by the boom inwardly of the point of mounting the dipper thereon.

In Fig. 3-the hoisting cable means may be of any conventional type, this feature not being material to the invention as the latter relates primarily to the dipper stick construction.

Referring now to the form of foot casting of Figs. 6 and 7, it will be seen that the rear portion 46 may act as a bumper block, the shipper shaft bearing being indicated at 47. The entire casting may beintegral, and

is provided with the side retaining plates 48. 48a, 49 and 49a, which plates are located rearwardly of the casting, theplates 48 and 48a being guide and retaining plates for afriction block 50 which has inwardly disposed grooves 51 for the reception of the retaining bolts 52 andQ52a. To secure these retaining bolts in position, the opposite plates 48 and 48a are provided with pairs of bolt holes 53 and 53a, 54 and 54a, extending through each of the plates in staggered relationship, so that when the bolts 52 and 52a are ready for insertion, as indicated in Fig. 7 to hold the friction block 50 in position, the insertion can be readily made as Fig. 7 will clearly indicate.

The retaining plates 49 and 49a are similarly provided with staggered pairs of bolt holes in an entirely analogous manner, and a friction block is secured within these plates in a manner exactly above described.

The casting of Fig. 6 is formed with a link or connecting portion 55 which is substantially I-shaped in cross-section to the forward end of which is secured by rivets, or other suitable means, the member 56, which has the upper and lower guiding and retaining plates 56a and 56b for the reception of the dipper stick. This member and plates are similar to the previously described member 18 and plates 18a and 18b, and serve the same purpose.

It will therefore be seen that there are provided simple yet rugged mountings for a dipper stick yieldable under lateral impacts without likelihood of fracture, and it will be apparent that many changes in the details of the herein specifically illustrated and described construction may be made without departing from the underlying inventive concept. Therefore it will be understood that it is intended and desired to embrace within the scope of this invention such modifications and changes as may be necessary to adapt it to varying conditions and uses.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent of the United States is:

1. In a power shovel, the combination with a boom, of a dipper stick carried by the boom and comprising a pair of vertically spaced members laterally flexible and vertically rigid, each of the vertically spaced members comprising a unitary elongated plate disposed in edgewise relationship with the other.

2. In a power shovel, the combination with a boom, of a dipper stick carried by the boom and comprising resilient vertically spaced unitary members disposed in edgewise relationship and yieldable under lateral impacts, but rigid in the plane of the digging stroke of the shovel.

3. In a power shovel, the combination with a boom, of a dipper stick carried by the boom and comprising resilient vertically spaced members yieldable under lateral impacts, but rigid vertically, and a connecting and reinforcing member for the dipper stick comprising a casting, having channels to receive and to support the dipper stick members and a bearing to receive a shipper shaft for operating the dipper stick upon the boom.

4. In a power shovel, the combination with a boom, of a dipper stick carried by the boom receive and to support the'dipper stick members and a bearing toreceive a shipper shaft for .permitting operation of the dipper stick.

upon the boom, and a casting secured to the dipper stick members at each end thereof to connect together the ends of the members.

5. In a power shovel, the combination with a boom, of a dipper stick carried by the boom and comprising a pair of unitary vertically spaced dipper stick members of resilient material disposed in edgewise relationship in the same vertical plane and bendable under lateral impacts but rigid in the plane of the digging stroke of the shovel to rigidly resist load stresses, the said members being flexible laterally to the extent of resiliency of the material composing the members.

6. In a power shovel, the combination with a boom, of a dipper stick carried by the boom and comprising a pair of vertically spaced unitary dipper stick members of resilient material, the members being disposed in edgewise relation with respect to each other in the same vertical plane, reinforcing means for each member serving also to connect the dipper stick to the boom, front and rear castings for each end of the dipper stick connecting together the said spaced members, and cable slack take up means mounted on the front casting.

7 In a power shovel, the combination with a boom, of a dipper stick carried by the boom and comprising a pair of vertically spaced unitary dipper stick members of resilient material forming a dipper stick freely flexible under lateral shocks to the extent of resiliency of the material but rigidly resistant to load stresses, the said members being disposed in edgewise relation to each other in the same vertical plane, front and rear connecting members for the ends of the spaced dipper stick members, and pawl and ratchet cable slack take up mechanism carried by the front connecting member.

8. In a power shovel, the combination with a boom, of a dipper stick carried by the boom and comprising a pair of vertically spaced members laterally flexible and vertically rigid, each of the vertically spaced members comprising a unitary elongated plate disposed in edgewise relationship with the other, and shipper mechanism on the boom comprising a part passing between the vertically spaced members aforesaid and affording a guiding function in relation thereto.

9. In a power shovel, the combination with a boom, of a dipper stick carried by the boom and comprising a pair of vertically spaced members laterally flexible and vertically rigid, each of the vertically spaced members comprising a unitary elongated plate disposed in edgewise relationship with the other, and shipper mechanism mounted on the boom including a transverse shaft part pivotally connecting the dipper stick with the boom and passing between the vertically spaced members of the dipper stick to aflord a guiding function thereto.

In testimony whereof I aflix my signature.

ERICH H. LIGHTENBERG. 

